Page 1 of 2 Next >>During the 1980s, Toyota had gradually moved up the IMSA ranks with Celicas built and raced by Dan Gurney's All American Racers (AAR). Having successfully competed in the GTU and GTO categories, the next logical step was the GTP class for full prototypes. To get a toe in the water, AAR hastily built a test and development prototype in 1987. It was crashed heavily during its very first test and not rebuilt.

Following a hugely successful, championship winning season with the GTO Celica in 1988, a full GTP program for 1989 received the green light from Japan. Importantly, one of the biggest rivals in IMSA's top class would be Nissan. While AAR was again commissioned to design, build and race the GTP car, Toyota also asked them to run a Japanese-built, Toyota-engined Dome 88C alongside the new machine, primarily for the longer distance events.

Tasked with the design of the GTP car were engineer Ron Hopkins and aerodynamicist Hiro Fujimori. Using their initials, the car was officially named the HF89 and a subsequent evolution the HF90. It was also referred to as the GTP Mk II as it was Toyota and AAR's second GTP design. Key in GTP design of the day was ground-effect aerodynamics and while not used on the Celica's AAR did have valuable experience with ground-effect on the team's Indy cars also designed by Hopkins.

Conventional in design, the GTP Mk II was built around an aluminium monocoque, which featured a honeycomb core for reinforcement. A separate rear subframe was used to mount the engine and gearbox. Suspension was by double wishbones on all four corners. Quite unusually, the springs and dampers were not mounted in-board to make more room for ground-effect tunnels. At the rear, they were mounted almost vertically for this very reason. Page 1 of 2 Next >>